Classical! The basic of the basics. The first music genre that any musician would learn to play is classical. Classical music is art music which is produced in the traditions of western music, including both liturgical (religious) and secular music. The major time divisions of classical music are as follows: the early music period, which includes the Medieval and the Renaissance eras; the Common practice period, which includes the Baroque, Classical, and Romantic eras; and the 20th century which includes the modern that overlaps from the late 19th-century, the high modern and contemporary or postmodern. The term "classical music" did not appear until the early 19th century, in an attempt to distinctly canonize the period from Johann Sebastian Bach to Beethoven as a golden age. The instruments currently used in most classical music consist of the instruments found in an orchestra or in a concert band together with several other solo instruments (such as piano, harpsichord, and organ). The symphony orchestra is the most widely known medium for classical music and includes members of the string, woodwind, brass, and percussion families of instruments. And, for the vocal practices, they changed over the classical period, from the single line monophonic Gregorian chant done by monks in Medieval period, to the complex polyphonic choral works of the Renaissance and subsequent periods, which used multiple independent vocal melodies at the same time.
Cool! (idk what to talk about) But, come to think of it, my experience about classical music is really really limited, though. And to be honest, musical instruments that I can actually play are only piano and guitar (and I'm not reallyy sure about the guitar part because I can only play the chords). But for me, music means having fun, and also enjoying the aesthetic part. I think the most popular yet easy classical music composition for piano is fur elise? Like, I play this a couple of times and people started to praise me and I was like, "yeah, haha, thanks. but I think this is pretty basic for pianist" and my head got bigger even though my piano playing is trash because I can't play it with perfect dynamics. And people started to praise me even more. But seriously.. Beethoven deserves this medal for making a simple piece sounds awesome.
Here's Beethoven's Fur Elise on Youtube. Let's give the copyrights to Beethoven himself, and the one who played this piece, and the one who uploaded it to youtube. Ps: the audio is a public domain.
Source: wikipedia.com, youtube,com